This disclosure relates to a connector apparatus to be interposed between measurement instrumentation and a flowing pipeline. In a pipeline flowing a product which is normally sold at a specified price per standard unit volume, it is necessary to measure the flow. One technique of measuring the flow through the pipeline involves the use of an orifice located in the pipeline. A differential pressure across the orifice is measured, and through the use of various techniques, the volume flow through the pipeline can be calculated. This technique requires that pressure be taken from each side of the orifice, and the two pressure signals are then used to obtain an incremental or differential pressure. In addition, it is often necessary to obtain either the upstream or downstream pressure which is being used as the static pressure.
Before a description of the present apparatus begins, it is helpful to set the stage by describing methods of connection of apparatus used heretofore. To this end, FIG. 1 has been included in the drawings to set forth the prior art. Briefly, FIG. 1 discloses a pipeline, including an orifice plate, and upstream and downstream connectors extending through suitable small fluid conduits to the suitable instrumentation. One instrument is incorporated which is responsive to the instantaneous differential pressure. As required, static pressure can also be obtained.
It is important to note, in FIG. 1, the method of connection that prevailed heretofore. In particular, the number of fittings and connections required to assemble the apparatus of FIG. 1 should be noted. On observing FIG. 1, it will be noted that there are thirty or more connections which have to be made. A connection is defined as a threaded joint which is made up between male and female threads. FIG. 1 shows a crossover having four legs, and hence this crossover requires four connections. It also shows tees at two locations, and each tee requires three connections with the three legs. Elbows are included and they all require two connections. All the valves and measuring instruments require at least one, and most require two connections. It is easy to see that the hand labor to install the prior art arrangement set forth in FIG. 1 is extensive. FIG. 1 is a worst case display of connections. The actual installations in the field may vary from the quantity of FIG. 1; while a typical installation may not be quite as complex, the nature of the problem is exemplified.
By contrast, the number of threaded connections (using the same definition) has been reduced by about two-thirds. This contrast is set forth readily on comparison of FIG. 2 with FIG. 1.
The large number of hand constructed male and female threaded joints is quite expensive to assemble, and yields a completed structure which is subject to twisting or warpage during assembly. Twisting may very readily occur on tightening of the many threaded joints. If nothing else, it is tedious to assemble that many threaded connections. It is tedious, requiring relatively good access to the work area so that craftsmen can get both hands on the parts as they are assembled, and then eventually tighten the threaded connections by use of a pair of adjustable wrenches. Without regard to the hand tools or the procedure used, it is sufficient to note that the structure shown in FIG. 1 and representative of the prior art is very tedious to assemble, typically costing far more in labor than the parts involved in the connective arrangement shown thereat.
It is even more difficult to service the structure shown in FIG. 1. Typically, accumulations of paraffin or hydrates will accumulate in the system, which create difficulties in operation of the pressure measuring instrument, to thereby handicap operation. Accumulated plugs (or wall solids) of paraffin can be removed by rodding the tubes. Rodding refers to the procedure in which a long thin rod is forced through the tubing and any accumulations of paraffin solids are broken and flushed from the tubing. The present apparatus provides a structure which is readily rodded; the structure shown in FIG. 1 is not normally rodded. In fact, rodding is initiated quite easily by unthreading a joint in the unitized connector of this disclosure, and the tubing and connector as thereafter reassembled. The possibilities of warpage and other damage are held to a minimum. This is enhanced by the fairly large gauge structural member disclosed herein, and the relative ease by which access in obtained to the passages through the unitized connector apparatus.
With the problems described hereinabove in mind, the present apparatus is summarized as a unitized connector apparatus for incorporation between measurement instrumentation and a pipeline differential pressure producing element for obtaining flow data. It is particularly suitable for connection therebetween for the purpose of conveying pressure through two separate lines, the pressure variables being communicated with a measuring instrument such as an instantaneous pressure differential meter or the like. This apparatus is, therefore, partially described as an elongate rectangular body having an axial passage drilled therethrough. The axial passage is intersected at both ends of the body by means of transverse lateral passages, and a central lateral passage is also included, all for the purpose of connecting the unified connector in a plumbed system for instrumentation.